Event Details

The phase space structure of our dark matter halo on small scales is an uncertain and much debated topic. It has become clear over recent years that this local structure could hold not just information about the merger and accretion history of the Milky Way but also about the particle properties of dark matter and the mechanisms involved in its production. In this way we can perhaps frame direct detection’s dependence on astrophysics, not as merely an uncertainty to be marginalised over, but instead as a central motivating question that might only be resolved by detecting dark matter. One can imagine a post-discovery era in which direct detection experiments can pivot into a mode of astronomy, in the manner of neutrinos or gravitational waves. I will describe how exciting these prospects are for the case of axion dark matter. Haloscope experiments designed to detect the conversion of axions into photons would observe a signal whose shape directly provides the speed distribution of dark matter. The excellent spectral resolution achievable in a resonant cavity experiment for example would allow a very fine measurement of the local halo, a feat unheard of in the context of WIMP dark matter. Furthermore, we have some new ideas for how one would extend conventional axion haloscope designs, using long aspect ratio cavities or dielectric disk setups, to directional axion searches. This would allow a measurement of the 3-dimensional velocity distribution and the possible discovery of a greater range of local dark matter substructure.